For each increase of 12 parts per billion (ppb) in exposure to nitrogen oxides, there was a 24 percent rise in the risk of diabetes and an 11 percent rise in the risk of hypertension. Exposure to particle pollution also appeared to increase the risk for having both diseases, but the evidence for this was weaker than for nitrogen oxides.
The study was released online Jan. 4 in advance of publication in an upcoming print issue of the journal Circulation.
Two previous studies suggested that traffic-related air pollution increased the risk of diabetes, but those studies did not include black Americans.
“A link between air pollution and the risks of diabetes and hypertension is of particular importance to African American women, because the incidence of both conditions is almost twice as high in African American women as in white women,” Coogan said in a Boston Medical Center news release. She added that black Americans also may tend to live in more highly polluted areas than white Americans.
“In addition, even a modest effect of air pollutants on the risks of hypertension and diabetes will have significant public health impact due to the high incidence of these conditions and the ubiquity of exposure to air pollution,” Coogan stated in the news release.